/*
** Nofrendo (c) 1998-2000 Matthew Conte (matt@conte.com)
**
**
** This program is free software; you can redistribute it and/or
** modify it under the terms of version 2 of the GNU Library General
** Public License as published by the Free Software Foundation.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
** Library General Public License for more details.  To obtain a
** copy of the GNU Library General Public License, write to the Free
** Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
**
** Any permitted reproduction of these routines, in whole or in part,
** must bear this legend.
**
**
** map16.c
**
** mapper 16 interface
** $Id: map016.c,v 1.2 2001/04/27 14:37:11 neil Exp $
*/

#include <noftypes.h>
#include <nes_mmc.h>
#include <nes_ppu.h>
#include <nes.h>

static struct
{
    int counter;
    bool enabled;
} irq;

/* mapper 16: Bandai */

static void map16_init(void)
{
    mmc_bankrom(16, 0x8000, 0);
    mmc_bankrom(16, 0xC000, MMC_LASTBANK);
    irq.counter = 0;
    irq.enabled = false;
}

static void map16_write(uint32 address, uint8 value)
{
    int reg = address & 0xF;

    if (reg < 8)
    {
        mmc_bankvrom(1, reg << 10, value);
    }
    else
    {
        switch (address & 0x000F)
        {
        case 0x8:
            mmc_bankrom(16, 0x8000, value);
            break;

        case 0x9:
            switch (value & 3)
            {
            case 0:
                ppu_mirror(0, 0, 1, 1); /* horizontal */
                break;

            case 1:
                ppu_mirror(0, 1, 0, 1); /* vertical */
                break;

            case 2:
                ppu_mirror(0, 0, 0, 0);
                break;

            case 3:
                ppu_mirror(1, 1, 1, 1);
                break;
            }
            break;

        case 0xA:
            irq.enabled = (value & 1) ? true : false;
            break;

        case 0xB:
            irq.counter = (irq.counter & 0xFF00) | value;
            break;

        case 0xC:
            irq.counter = (value << 8) | (irq.counter & 0xFF);
            break;

        case 0xD:
            /* eeprom I/O port? */
            break;
        }
    }
}

static void map16_hblank(int vblank)
{
    UNUSED(vblank);

    if (irq.enabled)
    {
        if (irq.counter)
        {
            if (0 == --irq.counter)
                nes_irq();
        }
    }
}

static void map16_getstate(SnssMapperBlock* state)
{
    state->extraData.mapper16.irqCounterLowByte = irq.counter & 0xFF;
    state->extraData.mapper16.irqCounterHighByte = irq.counter >> 8;
    state->extraData.mapper16.irqCounterEnabled = irq.enabled;
}

static void map16_setstate(SnssMapperBlock* state)
{
    irq.counter = (state->extraData.mapper16.irqCounterHighByte << 8) | state->extraData.mapper16.irqCounterLowByte;
    irq.enabled = state->extraData.mapper16.irqCounterEnabled;
}

static map_memwrite map16_memwrite[] = {
    {0x6000, 0x600D, map16_write}, {0x7FF0, 0x7FFD, map16_write}, {0x8000, 0x800D, map16_write}, {-1, -1, NULL}};

mapintf_t map16_intf = {
    16,             /* mapper number */
    "Bandai",       /* mapper name */
    map16_init,     /* init routine */
    NULL,           /* vblank callback */
    map16_hblank,   /* hblank callback */
    map16_getstate, /* get state (snss) */
    map16_setstate, /* set state (snss) */
    NULL,           /* memory read structure */
    map16_memwrite, /* memory write structure */
    NULL            /* external sound device */
};

/*
** $Log: map016.c,v $
** Revision 1.2  2001/04/27 14:37:11  neil
** wheeee
**
** Revision 1.1  2001/04/27 12:54:40  neil
** blah
**
** Revision 1.1.1.1  2001/04/27 07:03:54  neil
** initial
**
** Revision 1.1  2000/10/24 12:19:33  matt
** changed directory structure
**
** Revision 1.8  2000/10/22 19:17:46  matt
** mapper cleanups galore
**
** Revision 1.7  2000/10/22 15:03:13  matt
** simplified mirroring
**
** Revision 1.6  2000/10/21 19:33:38  matt
** many more cleanups
**
** Revision 1.5  2000/10/10 13:58:16  matt
** stroustrup squeezing his way in the door
**
** Revision 1.4  2000/08/16 02:50:11  matt
** random mapper cleanups
**
** Revision 1.3  2000/07/15 23:52:20  matt
** rounded out a bunch more mapper interfaces
**
** Revision 1.2  2000/07/11 05:03:49  matt
** value masking isn't necessary for the banking routines
**
** Revision 1.1  2000/07/11 03:14:18  melanson
** Initial commit for mappers 16, 34, and 231
**
**
*/
